Open AccessHuman Low‐Molecular‐Weight Urinary Urokinase
Author(s) -
SCHALLER Johann,
NICK Hanspeter,
RICKLI Egon E.,
GILLESSEN Dieter,
LERGIER William,
STUDER Rolf O.
Publication year - 1982
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1982.tb06676.x
Subject(s) - serine protease , serine , proteases , chemistry , biochemistry , urokinase , plasmin , isoelectric point , peptide sequence , homology (biology) , protein primary structure , isoelectric focusing , molecular mass , amino acid , protease , biology , enzyme , gene , genetics
Low‐molecular‐weight urokinase (molecular weight 33 100) was separated by analytical and preparative isoelectric focusing into five major subforms with isoelectric points between 8.7 and 9.6. These subforms are very similar in molecular weight, specific activity, amino acid composition and content of amino sugar and their N‐terminal sequence constellation is identical. Low‐molecular‐weight urokinase consists of two polypeptide chains connected by a single disulfide bridge. The N‐terminal region of the heavy chain (calculated M r 30700) exhibits homology within the first 46 residues analyzed, with the known primary structure of other serine proteases. The mini chain ( M r 2426), whose complete sequence was determined, consists of 21 residues which show homology with the primary structure of the C‐terminal region of the plasmin heavy chain. Based on sequence data and homology criteria with serine proteases a single‐chain urokinase precursor is postulated having a peptide bond constellation between heavy and light chain region compatible with the requirements for serine protease activation.